The Western Arctic is experiencing stronger storm surges, cyclonic systems, and enhanced waves and wind climates, causing flooding in coastal areas. At the historic site of Simpson Point on Qikiqtaruk - Herschel Island, flooding is an increasing threat, leading to the loss of archeological sites, damage to infrastructure, and rapidly reshaping the gravel and permafrost coastline. While the broad drivers of coastal flooding are known, such assessments lack applicability in the protection of vulnerable coastal sites with limited in situ monitoring. Here, we present the climatic and hydrological drivers of coastal floods on Qikiqtaruk. We used a network of six coastal wells to capture water level data across the 2024 and 2025 ice-free seasons, and paired with in situ weather, wind, and wave data, we quantified the drivers of flood severity and occurrence using Bayesian multivariate models. In 2024 and 2025 we captured 19 and 23 days of flooding, including the highest recorded water-level on 11 July 2025. We find that storm surges are the main driver of flood level, while wind and waves, particularly in the easterly direction strongly predict flood level under high surge conditions. These results inform the Coastal Flooding Prediction and Alerting Program by Environment and Climate Change Canada, and our methods are integrated into Yukon Parks’ Ecological Monitoring Program. This project highlights the importance of in situ monitoring to improve flood forecasting, which could be implemented elsewhere in the Canadian Arctic to conserve sensitive coastal areas.